“I don‚Äôt think I could seriously recommend building any application of importance or scale with a JS framework”. These days, a lot of the ‘big’ sites rely on a js framework. I just checked CNN.com and they are using prototype, ESPN.com are using jquery. And I think this trend is going to continue as these frameworks become more stable.

Good line, thanks. Supporting multiple runtimes is hard.

JavaScript is still very useful. But when building something atop varied JavaScript & CSS engines, you’re still bound by their intersection. As we go to mobile browsing, things get wild’n'wooly again, and few JavaScript frameworks yet describe which Linux browsers support them. A new abstraction layer doesn’t change the underlying capabilities, only the access methods to those existing capabilities.

re the Twitter “proprietary” thing, I noticed in the original article that Flash was dismissed on the basis of “proprietary”, but I was baffled why someone with that perspective would lock themselves into Apple’s hardware/software stack, or into Google’s database stack. Both of those are scarier, to me, than in not having runtime sourcecode, which you couldn’t use to modify someone else’s experience anyway!

(Welcome back to the land of the fully-living, btw.

jd/adobe

I mainly countered with Silverlight vs. Sproutcore as a lesser of two evils. Everyone who reads this regularly knows I would probably write a Flex app first.